I'm probably reading too much in it but the supposed site where Leeds Castle was does look in this Google Earth view like its general shape still resembles where a Castle/Motte and Bailey could have been (well it does to me ) despite all the changes to the area over time.

Relating to the Castle the following is an extract from Ralph Thoresby's 'Ducatus Leodiensis' 1715. I have put a modern 'f' where there was an f-like letter that was then often used for an 's'.

“The greateft part of this ancient and populous Town ftands upon the North Side of the River Are, upon an eafy Afcent; the Topographical Defcription of which is begun at the Weft Part, becaufe there of old ftood a famous Caftle with a Park adjoining, which, though now converted into leffer Inclofures, yet retains the Name of the Park to this day, and gives Denomination alfo to the Lane on the North Side thereof.

THIS Caftle was befieged by King Stephen in his March towards Scotland, Anno 1139; and here was the unfortunate Prince, King Richard II. lodged fome time before his barbarous Murder in Pontefract Caftle...

WHERE the Caftle of old ftood, is now a Capital Meffuage, and the ancient Mannor-houfe...

The Street that leads from the Caftle to the Town, is called the Bore-lane, or rather Burrow-lane...”.

It’s interesting why occasionally a modern ‘s’ was used rather than the fancy ‘f’ that I could not type and that a normal ‘f’ was used where there was an ‘f’ in a word. I had to look up what a Messsuage is and found it is “a dwelling house with outbuildings and land assigned to its use”.

I have in the past produced a series of historical maps of Leeds in the style of the modern OS ones. This one is the medieval which shows the site of the old moated manor house, in the location of the Scarborough public house.